Circuit Package

The present specification relates to systems, methods, apparatuses, devices, articles of manufacture and instructions for circuit packages.

According to an example embodiment, a circuit package, comprising: wherein the circuit package is configured to include a circuit; a brick having a first set of vias and a second set of vias; wherein the first set of vias are configured to be filled with a first material; wherein a first end of the first material is configured to be electrically coupled to the circuit; wherein a second end of the material is configured to form an electrical terminal on an external surface of the circuit package; and wherein the second set of vias are configured to be filled with a second material different from the first material.

In another example embodiment, each of the first set of vias are surrounded by the second set of vias.

In another example embodiment, each of the second set of vias are surrounded by the first set of vias.

In another example embodiment, rows of the first set of vias alternate with rows of the second set of vias.

In another example embodiment, the brick is a dielectric material.

In another example embodiment, the first material is an electrically conductive material.

In another example embodiment, the second material is a molding compound.

In another example embodiment, the second material does not extend fully through a subset of the second set of vias.

In another example embodiment, further comprising a substrate coupled to the circuit and the brick; wherein the second set of vias are an exit path for a substance located at an interface between the substrate and the brick; and wherein the substance is pushed into the second set of vias by the molding compound during encapsulation.

In another example embodiment, the substance is at least one of: air, gas, liquid, flux, or solvent.

In another example embodiment, the interface is a solder attach area.

In another example embodiment, further comprising a solder paste configured to electrically couple the first end of the first material to an electrical trace in the circuit.

In another example embodiment, the circuit package has a top-side and a bottom-side; the top-side of the package is configured to be coupled to a heat sink; and the electrical terminal at the second end of the first material is exposed on the bottom-side of the package and configured to be electrically coupled to another circuit.

In another example embodiment, the another circuit is in a circuit board upon which the circuit package is mounted.

In another example embodiment, the vias are created by at least one of: a drill, ablation, etching, forming, or hole punching.

In another example embodiment, the vias start on a first-side of the brick, pass completely through the brick, and end at a second-side of the brick.

In another example embodiment, the vias start on a first-side of the brick and end at one or more locations inside the brick.

In another example embodiment, the brick includes a saw lane between a first set of rows and a second set of rows; the first set of rows in the brick are configured to be coupled to a first circuit within the circuit package and the second set of rows in the brick are configured to be coupled to a second circuit within the circuit package; and the saw lane is configured to physically separate the first circuit from the second circuit.

In another example embodiment, the circuit is an RF circuit.

According to an example embodiment, a method of fabricating a brick to be embedded in a circuit package, comprising: forming a first set of vias in the brick; filling the first set of vias with a first material; wherein a first end of the first material is configured to be electrically coupled to a circuit within the circuit package; wherein a second end of the material is configured to form an electrical terminal on an external surface of the circuit package; and forming a second set of vias in the brick; wherein the second set of vias are configured to be filled with a second material different from the first material.

The above discussion is not intended to represent every example embodiment or every implementation within the scope of the current or future Claim sets. The Figures and Detailed Description that follow also exemplify various example embodiments.

Various example embodiments may be more completely understood in consideration of the following Detailed Description in connection with the accompanying Drawings.

While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that other embodiments, beyond the particular embodiments described, are possible as well. All modifications, equivalents, and alternative embodiments falling within the spirit and scope of the appended claims are covered as well.

Top-side cooled packages, as they can be called, provide better thermal performance in some applications. Due to the form factor of such packages, bricks (e.g. interposers) are used to electrically couple a set of top-side circuits, that are positioned closest to a heat-sink or other thermal management structure, to a bottom-side of the package that includes a set of I/O terminals for coupling to another device or circuit board.

Existing top-side cooled packages have a risk of molding compound voids forming underneath these bricks. The void are due to incomplete molding compound filling when air is trapped underneath the bricks as liquid molding compound encapsulated the top-side cooled package and imperfectly flows around the bricks.

Since the bricks are coupled to the top-side circuits with solder paste, these voids can permit solder to flow (i.e. create solder beads) between the brick's conductive traces that are used to electrically couple the brick's terminals to the top-side circuit's electrical contacts. During the solder paste reflow process, terminal to terminal shorting between the brick's conductive traces can occur resulting in a defective circuit package.

1 FIG. 100 100 101 102 104 106 108 represents an example set of circuit packagesbefore dicing. The example set of circuit packagesincludes one example circuit packageoutlined by saw lanes,,,.

101 110 112 110 The example circuit packageincludes a set of bricks(e.g. interposers), each having a set of ten terminalsin this example embodiment. The bricksare shared with neighboring circuit packages and are sawed in half during dicing.

114 116 100 118 100 118 1 FIG. A molding compound(e.g. encapsulant) is contained by a barrierand encapsulates the circuit packagesmounted on a laminate substrate. In various example embodiments, the circuit packagesinclude one or more of a set of circuits, a lead-frame, die-pad, a die/semiconductor chip, and/or a solder attach area, all of which are not explicitly shown in. Electrical traces within and/or on the laminate substrateelectrically couple these various dies/chips and other circuit elements.

100 118 114 110 112 112 Arbitrarily, a first-side (e.g. top-side) of the circuit packagesis on the laminate substrateside which can be mounted to a heat-sink for better cooling. A second-side (e.g. bottom-side) exposes the molding compound, the set of bricksand the set of ten terminals. The bottom-side is configured to be mounted and electrically coupled to another device or circuit board (not shown) by the terminals.

These so called “top-side cooled packages” are often used in various high-powered RF products, such as for WiFi access point base stations.

2 2 FIGS.A,B 200 101 represent a example viewsof the circuit packageafter dicing.

2 FIGS.A 101 202 101 202 204 206 208 In, the now diced example circuit packageincludes a set of half-brickssurrounding a perimeter of the example circuit package, each half-brickhaving now only a set of five terminals. A first-side (e.g. top-side)and a second-side (e.g. bottom-side)are shown.

210 202 206 114 212 118 204 202 204 A solder attach areabetween the bricksand the top-side substrateare shown. Due to voids (e.g. gaps, air bubbles, etc.) in the molding compound, a set of solder beadsform during reflow as the solder paste between electrical traces on the substrateand the terminalson the half-brickmigrates between several of the terminals.

2 FIG.B 210 212 shows a close-up of the solder attach areaand the solder beadsafter dicing.

Now discussed is a perforated brick (e.g. perforated interposer) having additional vias (e.g. through holes, passages, etc.) for minimizing or eliminating molding compound voids, particularly where the brick interfaces with another surface (e.g. a lead-frame, a circuit board, a semiconductor chip, a substrate, a solder pad, etc.).

The additional set of vias provide a set of paths for trapped substances (e.g. air, gasses, liquids, flux, solvents, etc.) to be expelled (e.g. evacuated, pushed out) to prevent mold voids, particularly at the critical solder attach areas. In some example embodiments, the vias enable the gases to be pushed out toward a bottom-surface of the circuit package.

In various example embodiments, the additional vias are formed by drilling through the bricks during fabrication. However the additional vias can also be formed in other ways, such as by ablation, etching, brick forming, hole punching, etc.

3 3 FIGS.A,B 300 302 306 308 306 312 represent an example comparisonbefore dicing of a first set of brickshaving a first set of vias, and a second set of brickshaving the first set of viasand a second set of vias.

302 304 308 310 314 302 308 The first set of bricksincludes a first example brick, and the second set of bricksincludes a second example brick. Saw lanesthat dice the bricks,are also shown.

302 308 118 In various example embodiments, these bricks,are fabricated separately before being mounted on the laminate substrate.

302 308 306 306 304 310 304 310 118 The bricks,can be fabricated starting with a thick organic board (e.g. a multi layer PCB) into which a first set of holes are drilled to create the first set of vias. The first set of viasare then filled with a first material (e.g. an electrically conductive material) to create a set of electrical paths between a first end of the bricks,and a second end of the bricks,. The set of electrical paths are designed to eventually electrically couple electrical traces on the laminate substrateto another device and/or circuit board (not shown).

314 304 310 The thick organic board is then sawed along the saw lanesto create individual bricks such as example bricksand.

308 312 312 312 310 310 3 FIG.B A second set of holes, however, are drilled into the second set of bricksto create the second set of vias, as shown in. The second set of viasare then completely or partially filled with a second material (e.g. a molding compound) later during fabrication. The second set of viascreate a set of exit paths between the first end of the second brickand a second end of the second brick. As mentioned above, these exit paths allow trapped substances (e.g. air, gasses, liquids, flux, solvents, etc.) to be expelled (e.g. evacuated, pushed out) during the encapsulation process to prevent mold voids, particularly at the critical solder attach areas.

308 312 312 112 204 312 506 118 In alternate example embodiments, one or more of the second set of holes are only partially drilled into the second set of bricks, at one or more depths, to create the second set of vias. In these alternate example embodiments, gas compression in the second set of viasmay be sufficient to enable the second material (e.g. a molding compound) to flow around the terminals,in the solder attach areas so as to move any voids into the second set of viasand away from between electrical traceson the substrate.

312 118 In other example embodiments, the second set of viasmay have other uses, such as to lighten the bricks, and/or increase or decrease attenuation of wireless signals transmitted from circuits on the laminate substrate.

4 4 FIGS.A,B 400 304 306 310 306 312 represent an example comparisonafter dicing of the first example brickhaving the first set of vias, and the second example brickhaving the first set of viasand the second set of vias.

5 5 FIGS.A,B 500 304 306 502 118 504 310 306 312 506 118 508 represent an example comparisonof the first example brickhaving the first set of viascoupled to a first set of electrical traceson the substratewith a first set of solder paste, and the second example brickhaving the first set of viasand the second set of viascoupled to a second set of electrical traceson the substratewith a second set of solder paste.

500 304 310 118 In the example comparisonthe bricks,are mounted to circuits on and/or in the laminate substratebefore later encapsulation, solder reflow, and dicing.

6 6 FIGS.A,B 600 304 306 114 310 306 312 114 represent an example comparisonof the first example brickhaving the first set of viasencapsulated with the molding compound, and the second example brickhaving the first set of viasand the second set of viasencapsulated with the molding compound.

600 304 602 502 The example comparisonshows that the first example brickcontains voidsbetween the first set of electrical traceswhich will permit solder bead shorts to form after solder paste reflow.

600 114 310 604 506 The example comparisonshows that since the molding compoundduring encapsulation can push substances away from the solder attach area, the second example brickhas no voidsbetween the second set of electrical traceswhich will prevent solder bead shorts from forming after solder paste reflow.

600 312 114 606 312 310 208 The example comparisonalso shows that the second set of viaswork so well that in some example embodiments the molding compoundcan further extend either partiallyor fully up through the second set of viasto the other-side of the second example brick(e.g. bottom-sideof the circuit package).

7 FIG. 700 represents an example set of instructionsfor fabricating a brick to be embedded in a circuit package.

702 704 706 An example instruction set in, forming a first set of vias in the brick. Next, in, filling the first set of vias with a first material, wherein a first end of the first material is configured to be electrically coupled to a circuit within the circuit package, and a second end of the material is configured to form an electrical terminal on an external surface of the circuit package. Then in, forming a second set of vias in the brick, wherein the second set of vias are configured to be filled with a second material different from the first material.

The instructions and/or flowchart steps in the above Figures can be executed in any order, unless a specific order is explicitly stated. Additionally, in some embodiments the instructions are implemented concurrently. Also, those skilled in the art will recognize that while one example set of instructions/method has been discussed, the material in this specification can be combined in a variety of ways to yield other examples as well, and are to be understood within a context provided by this detailed description.

It will be readily understood that the components of the embodiments as generally described herein and illustrated in the appended figures could be arranged and designed in a wide variety of different configurations. Thus, the detailed description of various embodiments, as represented in the figures, is not intended to limit the scope of the present disclosure, but is merely representative of various embodiments. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by this detailed description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussions of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.

Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize, in light of the description herein, that the invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.

Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the indicated embodiment is included in at least one embodiment of the present invention. Thus, the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.